Device for contactless, inductive power and data transmission, and preferred use thereof for identifying gas cylinders

ABSTRACT

A system containing a writing and reading unit with an antenna coil and at least one preferably elastic carrier in the form of a strip, on which is provided at least one mobile data memory which has a memory and operating circuit and, connected thereto, an elongate loop coil. The arrangement has the advantage that the mobile data memory can be provided on surfaces having virtually any degree of undulation. If a mobile data memory of this type encloses the circumference of a cylindrical object, then data transmission can be carried out in any desired radial spatial direction. The device is particularly suitable for identifying gas cylinders, in which case the elastic carrier, in the form of a strip, of a mobile data memory is placed around the casing of each gas cylinder, particularly in the region of the neck rings thereof.

BACKGROUND INFORMATION

The invention relates to a device for contactless, inductive power anddata transmission between at least one writing and reading unit with anantenna coil, and at least one mobile data memory, which is preferablyfitted to a portable object, with an antenna coil. The principle of acontactless transmission path of this type corresponds to a transformerwith a coupling factor which varies as a function of distance.

In the case of such devices, which are frequently referred to asidentity systems, a mobile data memory is first of all supplied withpower in a contactless manner by means of a writing and reading unit forthe purposes of activation and for enabling a data exchange. This isdone inductively in that a magnetic alternating field is generated inthe surrounding space by an antenna coil belonging to the writing andreading unit. When an object having a mobile data memory fitted thereonenters the magnetic alternating field, a voltage is induced in theantenna coil thereof. This provides the power required to operate themobile data memory. The data transmission which is now possible betweenthe writing and reading unit and the mobile data memory also takes placeinductively via the two antenna coils. Information identifying the typeand the current condition of the object provided with the respectivemobile data memory is, as a rule, communicated as data to the writingand reading unit for a wide variety of purposes.

The maximum distance between the mobile data memory and the writing andreading unit is, as a rule, up to one meter and, in practice, depends onthe dimensions of the antenna coils of the writing and reading unit andthe mobile data memory and on the respective ambient conditions.Particular problems arise when electrically conductive materials arepresent in the region of the alternating field, since the eddy currentsinduced therein cause the antenna resonant circuits of the writing andreading unit and/or of the mobile data memory to be detuned and/or themagnetic alternating field to be completely shielded from the antennacoil of the mobile data memory. As a result, the maximum range of thedata transmission can be restricted right up to the point of completeinterruption of said data transmission. A particularly unfavorablesituation is when a metallic surface of an object must serve as supportfor a mobile data memory.

To solve this problem, it is admittedly possible to fit a mobile datamemory by means of special mounts in such a way that an adequatedistance from the electrically conductive surroundings or support ismaintained. This ensures that the inductive power and data transmissionis influenced as little as possible by the otherwise occurring resonantfrequency shifts in the antenna resonant circuits of the mobile datamemory or the writing and reading unit. However, it is disadvantageousthat the mobile data memories project sometimes to a large extent overthe outer surfaces of the objects and, consequently, there is aconsiderable risk of breaking. Furthermore, mounts protruding in thisway will make it more difficult to transport and use, in particular,objects which are difficult to handle on account of their shape, forexample, and, if appropriate, have a high dead weight.

If a mobile data memory is fastened to a preferably portable object tobe identified, then data transmission without additional positioningoperations is only possible if the sum of the minimum distance to bemaintained between the mobile data memory and the writing and readingunit and the largest edge lengths thereof is always less than the rangeof the device under the respective ambient conditions. Only in simplecases, however, is it ensured that the mobile data memory, when manuallyor automatically approaching the writing and reading unit, is alwayssituated in the field region thereof in a manner independent ofposition. Further problems thus arise in the case of parallelepipedalobjects having relatively large dimensions or in the case of objectshaving curved outer surfaces. In this case, prior positioning isfrequently required for an automated data exchange, for example, wherean object that is provided with a mobile data memory travels on aconveyor belt past a stationary writing and reading unit. It istherefore necessary, under certain circumstances, that the object berotated until a mobile data memory, situated on a remote side in themost unfavorable case, is facing the writing and reading unit. This isparticularly difficult with objects which have a high dead weight orcurved outer surface and the mobile data memories consequently have tobe fitted on poorly definable, non-planar surfaces.

Further problems arise when a plurality of objects, each provided with amobile data memory, are simultaneously brought up, for example on apallet, in a box or other transport device, to a writing and readingunit. On the one hand, particularly when the objects have, for example,a cylindrical shape, the mobile data memories on some objects mayrandomly assume a position facing away from the respective writing andreading unit. A type of shading thus occurs, which is particularlypronounced in the case of objects produced from a metallic material. Onthe other hand, in conventional identity systems, as a rule only onemobile data memory is allowed to be situated in the magnetic alternatingfield of the writing and reading unit during the data exchange, in orderto maintain proper functioning. Certain identity systems generate largemagnetic fields within which the data exchange between a mobile unit anda writing and reading unit occurs. The relatively large magnetic fieldsproduced by such systems permit the data exchange to occur largelyindependent of the relative positioning of the mobile unit and thewriting and reading unit. Nevertheless, this advantage is nullified assoon as a plurality of objects are situated at a small distance from oneanother, for example in a common transport container. Due to thissimultaneous presence of a plurality of mobile data memories in thefield region of a writing and reading unit, it is no longer possible,without a (possibly considerable) additional software and hardwareoutlay, to set up a data transmission to each individual mobile datamemory in an unambiguously distinguishable manner.

SUMMARY OF THE INVENTION

The present invention is directed to a device that provides for reliabledata transmission between a mobile data memory and a writing and readingunit. The device of the present invention provides such a reliable datatransmission independently of the current relative positions of themobile data memory and the writing and reading unit, even when themobile data memory is attached to an electrically conductive surface ofan object and even when a plurality of other mobile data memoriescorresponding to other objects are positioned within the field range ofthe writing and reading unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and advantageous embodiments thereof are explained in moredetail with reference to the figures, which are explained briefly below.In the figures

FIG. 1 shows a side view of a preferred embodiment of a mobile datamemory of the device according to the invention,

FIG. 2 shows a side view of a preferred embodiment of a writing andreading unit of the device according to the invention, and

FIG. 3 shows an example of the fitting of mobile data memories of thedevice according to the invention in the region of the neck rings of gascylinders according to a preferred use of the device according to theinvention.

DETAILED DESCRIPTION

The device for contactless, inductive power and data transmissionaccording to the invention contains at least one writing and readingunit with an antenna coil, and at least one mobile data memory which hasa memory and operating circuit and, connected thereto, an elongate loopcoil, which are provided on a preferably elastic carrier in the form ofa strip. It is advantageously possible to use a flexible printed circuitboard as the carrier in the form of a strip for the elongate loop coil.The arrangement has the advantage that the mobile data memory can beprovided on surfaces having virtually any degree of undulation.

The device according to the present invention can preferably be used foridentifying gas cylinders. The elastic carrier of a mobile data memoryis in the form of a strip and is placed around the casing of each gascylinder, particularly in the region of the neck rings thereof. As aresult, it is possible, in every case and independently of the currentradial position of a writing and reading unit with respect to the axisof a gas cylinder, to ensure reliable data transmission even if aplurality of gas cylinders should be standing close together in a crateserving as transport container. Since gas cylinders are composed of ametallic material, it is advantageous in this case that the carrier inthe form of a strip for the elongate loop coil has a certain thickness,and that the loop coil is provided or incorporated on that side of thecarrier which is remote from the neck ring of a gas cylinder. A flexibleprinted circuit board as the carrier in the form of a strip usuallyalready has a thickness sufficient for this purpose.

The device according to the invention is thus preferably suitable forbeing fitted on and identifying objects which have a curved, inparticular cylindrical, surface. If these objects are produced, forexample, from an electrically non-conductive material, then the carrierin the form of a strip need not have an appreciable thickness. In such acase, an adhesive tape or an adhesive film, for example, can serve asthe carrier. The elongate loop coil and the memory and operating circuitof each of the mobile data memories are placed on such a carrier. Fortransport purposes, these adhesive-tape-like carriers can be placed, forexample, on cardboard-like supports, which are coated at least on oneside, and can be drawn off from said supports, in a manner free fromdamage, for the purpose of final application to an object to beidentified complete with a unit comprising an elongate loop coil and amemory and operating circuit. On account of the self-adhesive propertiesof the carrier, auxiliary means for retaining the carrier, such aslocks, for example, are dispensed with in this case. It is also possibleto provide a multiplicity of units, each comprising an elongate loopcoil and an associated memory and operating circuit, one behind theother like a row on the adhesive side of a continuous adhesive tape, andto fabricate the latter in the form of adhesive rolls. With rolls ofthis type, it is then possible to equip, rapidly and without anyappreciable outlay, a potentially very large number of objects, forexample a stock of gas cylinders running into thousands, which are to berendered accessible to contactless identification, with a mobile datamemory configured according to the invention.

The invention and further advantageous embodiments thereof are explainedin more detail with reference to a preferred exemplary embodimentillustrated in FIGS. 1 and 2.

According to the illustration in FIG. 1, the mobile data memory MDS has,according to the invention, an elastic carrier TB in the form of astrip. The antenna coil SP of the mobile data memory MDS is provided onsaid carrier. Said coil has the form of a planar, elongate loop coil.The coil may have a plurality of turns, which is not illustrated in FIG.1 for reasons of clarity. The coil is closed at one short end side E1 ofthe carrier TB in the form of a strip, whereas at the other short endside E2 it is connected to a memory and operating circuit SE. Thecircuit serves, in particular, to store so-called identity data of anobject provided with the mobile data memory, to supply power to themobile data memory, and to enable inductive data transmission via theloop coil SP with a writing and reading unit. The elastic carrier TB inthe form of a strip may advantageously be designed, for example, in theform of a flexible printed circuit board, on which the elongate loopcoil SP and the memory and operating circuit SE can be provideddirectly, for example as a so-called ASIC.

The inventive design, which is illustrated by way of example in FIG. 1,of a mobile data memory MDS has a multiplicity of advantages. On the onehand, the inductance of the loop coil SP is independent of the curvatureof the elastic carrier TB, in the form of a strip, in a plane lyingperpendicular to the coil face, as long as there is no overlapping ofthe loop beginning and end at the short end sides E1, E2 of the carrierTB. The carrier TB and hence the entire mobile data memory MDScomprising loop coil SP and memory and operating circuit SE can, for thepurpose of mounting, be placed onto a surface which is planar withregard to the short loop edge. This surface can have virtually anydesired curvature or contour in the direction of the long loop edge.Thus, the carrier can be placed, for example, around a 90-degree edge ofa parallelepipedal object, such as the edge of the housing of arefrigerator. It is then possible without any problems to effect datatransmission in two perpendicular spatial directions. Furthermore, themobile data memory MDS according to the invention is particularlysuitable for being placed onto circularly curved surfaces, for exampleonto the outer sides of cylindrical objects. The carrier 7B can beformed into a variety of shapes: it can be formed into a flat andslotted shape, into an easily bent open or resilient ring, collar, orclasp, or even into a formless strip. Simple mounting is ensured in eachof these designs. In an application for identifying cylindrical objects,such as bottles, for example, fitting is possible independently of therelevant radius of curvature and the circumference of the object. Thearea covered by the loop coil is in this case parallel to the surface ofthe object. If the cylindrical object is enclosed virtually completely,then data transmission is possible radially in all spatial directionsaround the axis of the cylindrical object.

The short end sides E1 and E2 of the elastic carrier TB in the form of astrip can advantageously be connected to a releasable closure device.FIG. 1 illustrates a closure device V in the form of a strap. Closuredevice V has a row of retaining holes E, and the closure device V isplaced for this purpose on one short end side E2 of the carrier stripTB. On side E2, the retaining holes E engage a retaining stud K of thecarrier TB, depending on the relevant circumference of a cylindricalobject. device V may be designed such that it can be lead-sealed. On theother hand, the carrier TB can also be bonded on.

The distance between the plane of the loop coils SP and the surface ofthe object need only be a few millimeters, even in the event ofelectrical conductivity of said surface, with the result that it ispossible to use elastic carriers in strip form which have only a smallthickness. The enlargement of the diameter of the object by the emplacedmobile data memory is scarcely noticeable. When the mobile data memoryis mounted on an electrically conductive surface, it is possible tocompensate for the detuning of the mobile data memory caused by theelectrically conductive surface by appropriately selecting the effectiveresonant circuit capacitance of the coil of the memory.

Writing and reading units can be permanently mounted and connected to anexternal computer. In the event of mobile use, they can also be designedin the form of portable hand-held units. FIG. 2 illustrates an exampleof a portable design of a writing and reading unit SLG. The lattercontains a separate hand-held unit and serves for a type of "remotecontrol" of mobile data memories. This preferably has an operatingkeyboard and a display device, in particular in the form of an LCDdisplay, by means of which so-called "identity data" can be called froma mobile data memory and also updated and written back. The hand-heldunit HG of the writing and reading unit SLG is connected via aconnection cable AK to an antenna coil AT, which is preferably providedon a separate, elastic carrier T. A flexible printed circuit board isonce again preferably suitable for this purpose and may advantageouslyhave an approximately c-shaped cross section. By means of a retainingrod ST, the carrier T with the antenna coil AT of the writing andreading unit SLG can be brought in a simple manner into the spatialvicinity of a specific mobile data memory according to the inventioneven when the latter is fitted to an object which, for example, ispacked close together with further objects of identical form in atransport container.

The device according to the invention is particularly suited to beingused for identifying gas cylinders.

Gas cylinders are composed of electrically conductive materials and havea cylindrical shape with annularly curved outer surfaces of varyingcircumference. They are used in industry in very large numbers and arefilled with a wide variety of technical gases which are required forextremely diverse purposes, for example in the chemical industry. Boththe manufacturer of technical gases, which frequently has to manage astock of gas cylinders comprising several million items, and therespective purchaser of technical gases have a considerable interest,both of an economical nature and in terms of safety, in an exactidentification of each gas cylinder and the processing of the currentspecific characteristic values thereof. Significant technicalcharacteristic values are, in particular, the respective cylindernumber, size, current contents, the date when the cylinder will next bechecked and the like. Furthermore, it is important to acquire the exacttransport route and whereabouts of each cylinder over relatively longperiods of time in the past.

In the example of FIG. 3, four gas cylinders G1 . . . G4 are broughttogether standing closely adjacent in a crate GB for the purpose oftransport. According to the invention, an elastic carrier, in the formof a strip, of a mobile data memory MDS1 . . . MDS4 is in each caseplaced around the casing of each gas cylinder G1 . . . G4, preferably inthe region of the neckrings H1 . . . H4 thereof, which neckrings areused to mount the cylinder valves and to screw on a cover cap D1 . . .D4 which protects the cylinder valves.

An arrangement of this type has the particular advantage thatcontactless power and data transmission from a writing and readingdevice to a mobile data memory fitted to the neck region of a gascylinder is possible even if the latter is situated in the interior of acrate which is completely filled with further gas cylinders and,possibly, even if a plurality of crates are stacked one over the other.The data transmission can take place from any desired spatialdirections, on account of the advantageous configuration of the mobiledata memories. Consequently, it is not necessary to rotate the gascylinders with respect to the their cylinder axis or even to remove themtemporarily from the crate. Furthermore, the handling of individual gascylinders is in no way impeded by a mobile data memory placed in theform of a collar around the neck ring. Finally, the fitting of themobile data memories in the neck region involves only a very slight riskof mechanical damage.

It is advantageously possible here to use a writing and reading deviceSLG, designed in accordance with the illustration of FIG. 2, with aseparate antenna coil, which is provided on a c-shaped carrier fastenedto a retaining rod.

What is claimed:
 1. A system for contactless, inductive power and datatransmission independently of spatial direction, comprising:a) at leastone writing and reading unit having an antenna coil; and b) at least onemobile data memory, the at least one memory unit including:i) a memory;ii) an operating circuit; iii) an elongate loop coil coupled to thememory and the operating circuit; and iv) an elastic carrier on whichthe memory, the operating circuit and the elongate loop are provided,wherein the elastic carrier and the elongate loop coil are configured sothat the elastic carrier and the elongate loop coil are placed onto acasing exterior of an object provided with the mobile data memory andenclose said object substantially in the shape of a ring.
 2. The systemaccording to claim 1, wherein the elastic carrier comprises a flexibleprinted circuit board for supporting the elongate loop coil, the memory,and the operating circuit.
 3. The system according to claim 1, whereinthe elastic carrier includes a plurality of short end sides forconnection to a releasable closure device.
 4. The system according toclaim 1, wherein the elastic carrier comprises one of an adhesive tapean adhesive film for supporting the elongate loop coil, the memory, andthe operating circuit.
 5. The system according to claim 1, wherein theantenna coil of the writing and reading unit is provided on a separateelastic carrier.
 6. The system according to claim 5, wherein theseparate elastic carrier comprises another flexible printed circuitboard.
 7. The system according to claim 5, wherein the separate elasticcarrier has an approximately c-shaped cross section.
 8. The systemaccording to claim 5, further comprising a retaining rod, the retainingrod being fitted to the separate elastic carrier.